The most controversial and potentially most dangerous therapies in dental pharmacology involve the conscious sedation of anxious pediatric patients. The April 22-24, 1985 NIH Consensus Development Conference on "Anesthesia and Sedation in the Dental Office" recognized the liabilities of pediatric sedation and the paucity of controlled clinical trials evaluating sedation treatment modalities. (1) The followup NIDR sponsored research workshop on dental anxiety needs (September 12-13, 1985) recommended controlled clinical trials of sedation modalities using reliable and reproducible assessment measures. (2) The general goal of this proposal is to evaluate the safety and efficacy of commonly used pediatric conscious-sedation therapies. Emphasis is directed towards pharmacologic approaches that use a narcotic as the primary or adjunctive agent. Because young child patients appear particularly at risk, this proposal will focus on therapeutic and possible adverse responses of this unique population. The efficacy of narcotic techniques will be compared to accepted non-narcotic methods to provide an assessment of relative risks and benefits. Measurements of behavioral efficacy and physiologic stability will be duplicated to determine assessment techniques most applicable to research and clinical practice. The specific aims are to perform three controlled clinical trials of sedation efficacy and toxicity using randomized and double-blind methodologies. These clinical trials will assess the pharmacologic modalities most commonly used in pediatric dentistry. 1. A dose-response analysis of intramuscular meperidine in a preschool pediatric dental population to determine its optimally safe and effective dose. 2. A comparison of the optimal dose of meperidine to chloral hydrate 50 mg/kg and a placebo in a pediatric population to assess the relative efficacy of a narcotic technique when compared to an accepted standard and control. 3. A comparison of meperidine, promethazine, meperidine/promethazine full dosages and meperidine/promethazine half dosages and a placebo in a pediatric population to assess the therapeutic rationale for combining a narcotic with a sedative. The use of multiple behavioral assessment scales and multiple physiologic measures will permit a simultaneous evaluation of the sensitivity and reliability available methodologies for determining clinical safety and efficacy.